Spinal implants for rotationally adjusting vertebrae

Abstract

A spinal implant adapted to be positioned within a disc space between adjacent vertebrae includes a first intradiscal element, a second intradiscal element, and a coupling mechanism. The first and second intradiscal elements include respective first and second outer surfaces adapted to be positioned adjacent an endplate of respective first and second adjacent vertebrae. The first and second intradiscal elements further include respective first and second medial surfaces that are opposite the respective first and second outer surfaces, where the second medial surface is adapted to generally face the first medial surface upon assembly of the first intradiscal element with the second intradiscal element. The coupling mechanism is associated with the first and second medial surfaces and is adapted to provide relative rotational movement between the first and second intradiscal elements in a plane generally parallel with the first and second medial surfaces.

What is claimed is: 
     
       1. A spinal implant adapted to be positioned within a disc space between adjacent vertebrae, the implant comprising:
 a first intradiscal element comprising a first outer surface adapted to be positioned adjacent an endplate of a first one of the adjacent vertebrae and comprising a first medial surface that is opposite the first outer surface, wherein the first intradiscal element comprises a first proximal flange portion that extends generally perpendicularly to a longitudinal axis of the first intradiscal element, and a first borehole extending through the first proximal flange portion, wherein the first proximal flange portion is configured to be positioned against a side aspect of a first vertebra for receipt of a bone screw through the first borehole in a trajectory that is generally parallel with the longitudinal axis of the first intradiscal element, and wherein the first intradiscal element comprises a cap configured to be placed on the first proximal flange portion, the cap comprising holes formed in each side of the cap that align with the first borehole when the cap is placed on the first proximal flange portion, the cap having a thickness in a medial portion selected to provide rotational pressure on a side of the vertebra to which the first proximal flange portion is affixed; 
 a second intradiscal element comprising a second outer surface adapted to be positioned adjacent an endplate of a second one of the adjacent vertebrae and comprising a second medial surface that is opposite the second outer surface and adapted to generally face the first medial surface upon assembly of the first intradiscal element with the second intradiscal element; 
 a coupling mechanism that is associated with the first and second medial surfaces and that is adapted to provide relative rotational movement between the first and second intradiscal elements in a plane generally parallel with the first and second medial surfaces and about an axis at a center portion of the first and second medial surfaces; and 
 a rotational movement resistance mechanism adapted to resist rotational movement from a plurality of incremented relative rotational positions of the first intradiscal element in relation to the second intradiscal element. 
 
     
     
       2. The spinal implant of  claim 1 , wherein the coupling mechanism comprises a post element extending from the center portion of one of the first and second medial surfaces and an aperture provided in the center portion of the other of the first and second medial surfaces, the post element and aperture adapted to be coupled together. 
     
     
       3. The spinal implant of  claim 2 , wherein the post element comprises a bulbous distal end, and the aperture comprises an enlarged lower portion that receives the bulbous distal end of the post element. 
     
     
       4. The spinal implant of  claim 3 , wherein the coupling mechanism further comprises a snap ring adapted to be positioned about a neck of the post element proximal of the bulbous distal end, and the aperture further comprises a circumferential chamber into which the snap ring is able to be engaged. 
     
     
       5. The spinal implant of  claim 1 , wherein the second intradiscal element has formed therein at least one borehole adapted to receive a second bone screw for affixing the second intradiscal implant to the first one or the second one of the adjacent vertebrae. 
     
     
       6. The spinal implant of  claim 1 , wherein the first and second outer surfaces are ridged for secure engagement with the endplates of the adjacent vertebrae. 
     
     
       7. The spinal implant of  claim 1 , wherein the first and second outer surfaces comprise spike elements for secure engagement with the endplates of the adjacent vertebrae. 
     
     
       8. The spinal implant of  claim 1 , wherein the first intradiscal element comprises a first engagement mechanism adapted to be engaged by a distal tip of a first hand-held instrument, and the second intradiscal element comprises a second engagement mechanism adapted to be engaged by a distal tip of a second hand-held instrument, the first and second engagement mechanisms being configured to provide the relative rotational movement when acted upon by the first and second hand-held instrument in opposite directions. 
     
     
       9. The spinal implant of  claim 1 , wherein at least one of the first and second intradiscal elements is tapered from a proximal end to a distal end. 
     
     
       10. The spinal implant of  claim 1 , wherein at least one of the first and second intradiscal elements is tapered from a first side to a second side. 
     
     
       11. The spinal implant of  claim 1 , wherein the first and second intradiscal elements each have formed therein at least one fusion aperture extending from their respective outer surfaces to their respective medial surfaces, the at least one aperture in each of the first and second implants adapted to permit bone growth through the implant for spinal fusion. 
     
     
       12. The spinal implant of  claim 11 , wherein at least one of the first and second intradiscal elements have at least one viewing aperture extending from a side surface of the intradiscal element to one of the at least one fusion aperture, the at least one viewing aperture being configured to provide a view of bone growth through the fusion aperture through use of an imaging machine. 
     
     
       13. The spinal implant of  claim 1 , wherein the spinal implant is generally rectangular. 
     
     
       14. The spinal implant of  claim 13 , wherein the spinal implant is sized and configured to extend laterally across a disc space, from one lateral aspect of the disc space to the opposite lateral aspect of the disc space.